Method of forming coherent metallic members



May 17, 1966 H. s. sPAclL METHOD OF FORMING COHERENT METALLIC MEMBERS Filed Oct. 22, 1965 IQN..

l jected to hydrogen.

United States Patent() 3,251,684 METHOD F FGRMING COHERENT METALLIC MEMBERS HenryS. Spacil, Schenectady, N.Y., assignor to General Electric Company, a corporation of New York Filed Oct. 22, 1965, Ser. No. 507,609 8 Claims. (Cl. 75-200) This application is a continuation-impart of my copending application tiled January Q, 1963, as Serial No. 249,070, and assigned to the same Iassignee as the present application.

This invention relates to methods of forming coherent metallic members and more particularly to methods of forming coherent metallic members yfrom metallic halides.

A method of producing liron powder is set forth in United States letters Patent, 2,418,148, Williams et al., wherein ferrous chloride, which is maintained below its melting point, is subjectedto hydrogen. Another method of forming iron powder is described in United States Letters Patent 2,663,633, 'wherein gaseous ferrous chloride, which is maintined above its melting point, is sub- In United States Letters Patent 2,664,352, Darner et al., production of iron powder is described wherein ferrous chloride in liquid form is Isprayed into a chamber into which hydrogen is introduced.

In each of the above patents, la method is disclosed for ,producing iron powder which powder must be subsequently processed `by conventional techniques to produce useful coherent articles or shapes. Itwould be desirable to produce coherent metallic members by the reduction of their respective metallic halides. Such la method would be advantageous in providing directly the coherent metallic member, The presen-t application is directed to methods of forming coherent metallic members by reduction from their respective metallic halides.

It is an object of myginvention to provide coherent metallic members.

-It is another object of my invention to provide a coherent metallic member from -its respective metallic halide.

I-t is another object of my invention to provide a coherent metallic member trom a mixture of metallic halides.

It is a ifurther object of my invention to provide a coherent .metallic member from at least one mixed metallic halide.

It is a further object of my invention to provide a coherent metallic member containing at least one inert non-metallic iller material.

It is a still further object of my invention to provide a coherent metallic member containing yat least one inert metallic ller material. l

In carrying outgmy invention in one form, a method of forming a coherent metallic member comprises forming at least one metallic halide powder into a preshaped powder member, positioning the .preshaped member within a chamber, introducing into the chamber a stream of 'gas consisting essentially of hydrogen, and heating the member to a temperature in a temperature range having a lower limit in Ia range determined Iby the hydrogen halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of the member and with the member in a range from 0.001 to 0.01, and an upper limit ina rangedetermined by the metallic halide vapor pressure multiplied iby the number of halide atoms per metallic atom in a range from 0.001 to 0.01 whereby the member is reduced to a coherent metallic member.

These and various objects, features and advantages of the invention will .be better understood from the -follow- 3,251,684 Patented May 17, 1966 ICC ing description taken in connection with the accompanying drawing in which:

The single iigure of the drawingis a graph plotting the y standard free energy of formation of metallic chlorides per mole of chlorine in kilocalories versus temperature in degrees centigrade.

The present invention is directed to methods of forming coherent metallic members by the reduction of their respective halides under speciiic conditions. Nickel. cobalt, chromium, silver, copper .and iron are produced from their respective halides. Various alloys are also formed by appropriate mixtures of the respective metallic halides. nickel-chromiurn-iron, iron-chromium, iron-nickel-chromium, iron-nickel-cobalt, iron-cobalt, iron-nickel, coppe-rnickel-iron, and Copper-nickel-cobalt, are produced :by this method.

I discovered unexpectedly that at least one metallic h halide could be formed into ya preshaped member and reduced under specific conditions to provide a coherent metallic member. These speciiic conditions require that the metallic halide be subjected to a stream of gas, the essential active reducing ingredient of which is hydrogen. It is also necessary to employ a temperature range where the reduction of the -halide tends to occur to a signiiicant extent. I found further that the preshaped halide member must be heated to a temperature in a temperature range having la lower limit determinedv by the hydrogen halide partial pressure to the 'hydrogen partial pressure ratio in equilibrium with the metal of the member and with the member in a range from 0.001 to 0.01. I found also that the upper temperature limit is a range determined by the metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in a range from 0.001 to `0.01. Under these conditions, I discovered that a preshaped metallic halide member couldibe formed into a coherent metallic member.

I discovered further that a mixture of metallic halides could also be formed into a preshaped member and reduced under the albove conditions rto provide a coherent metallic member. tFor example, such a halide mixture would include the mixing of at least two metallic halide powders such as nickel chloride and chromium trichloride to provide a mixture which is subsequently formed into a preshaped member. The resulting coherent metallic member is a nickel-chromium alloy. The subject method is also applicable to forming at least one mixed metallic halide into a Apreshaped member which is reduced subsequently under the above conditions to provide a coherent metallic member. Suchv a mixed halide would include at least two metallic components in the halide, such as nickel and cobalt.

At least one metallic halide and a metal which will react with the metal reduced from the metallic halide are also formed into a p'reshaped member as disclosed above and reduced to a coherent metallic member. In the formation oi such a preshaped member, at least one metallic halide, a mixture of metallic halides or at least one mixed metallic halide is employed. The reacting metal can be a single metal, a metal mixture, or a metallic alloy, or derived from a metal compound, a metal compound mixture, ora mixed metal compound. For example, a nickel halide, NiCl2, and a copper halide, CuCl, comprising a mixture of metallic halides and a reacting metal zirconium in the form of zirconium hydride powder are formed together into a preshaped member which is reduced in the manner described above. A reacting metal in the form of ya metallic alloy such as an iron-tungsten-carbon.alloy in powder form and a mixture of metallic halides of nickel chloride, ferrous chloride, chromium chloride, and cobalt chloride are formed together into a preshaped member.

For example, nickel-copper, nickel-chromium,- I

The coherent metallic member which is formed from the preshaped member is a nickel-iron-chromium-cobalt-tungsten-carbon alloy.

I found further that at least one inert metallic filler or at least one inert non-metallic ller can be combined with at least one metallic halide -to form the preshaped member. Furthermore, I found that such a metallic or nonmetallic filler could be combined with at least one metallic halide and at least one other reacting metal to form a coherent metallic member. For example, a metallic filler of molybdenum in powder form is mixed with a metallic halide such as a copper chloride to produce a coherent metallic member of copper metal with molybdenum particles therein. A non-metallic filler of magnesium silicate powder is combined with a mixture of metallic halides of nickel chloride and chromium chloride to form upon subsequent reduction a nickel-chromium Ialloy with magnesium silicate particles therein. A nonmetallic tiller of titanium oxide powder is combined with a metal compound of titanium hydride and with a mixture of metallic halides of ferrous chloride, nickel chloride, and cobalt chloride to form an iron-nickel-cobalt-titanium alloy with titanium oxide particles therein.

lIn the single figure of the drawing, the standard free energy of formation of metallic chlorides per mole of chlorine in kilocalories is plot-ted against temperature in degrees centigrade.

Broken lines 10 and 11 set forth a range for the minimum standard free energy of formation of metallic chlorides per mole of chlorine in kilocalories which is necessary for each of the metallic chlorides set forth on the graph to be reduced to its respective coherent metal at a hydrogen pressure of one atmosphere. Broken lines 10 and 11 define a lower temperature limit determined by the hydrogen chloride partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of the member and with the member in a range from 0.001 to 0.01. On each line identifying a particular metallic chloride, a point 12 defines the temperature at which the vapor pressure of the metallic chloride multiplied by the number of of chlorine atoms per metal atom is equal to 0.001. A point 13 on each line defines the temperature at which the vapor pressure of the metallic chloride multiplied by the number of chlorine atoms per metal latom is equal to 0.01. The metallic chlorides yfor which points 12 and 13 are plotted to the right and above the lower temperature limit range are reducible to their respective coherent metals without undue loss of metal by evaporation of metallic chloride. The metallic chlorides whose points 12 and 13 are plotted to the left and below the lower temperature limit range are not reducible. Thus, it is feasible to reduce silver chloride, cuprous chloride, nickel chloride, cobalt chloride, Iferrous chloride and chromiumichloride to their respective coherent metals. It is not feasible to reduce cadmium chloride, zinc chloride or manganese chloride to their respective coherent metals. `In the latter metallic chlorides, chloride evaporation occurs more rapidly -than reduction of 4the metal by hydrogen.

While the subject graph sets forth a plurality of metallic chlorides which are suitable in the present method, similar graphs can be prepared for suitable metallic bromides and metallic iodides. When a mixture of metallic chlorides, or a mixed metallic chloride which may be combined with a reacting metal, or a filler or both, to provide a coherent metallic member, a temperature is selected from the above graph which temperature is within the respective temperature range .for reduction of the individual metallic chlorides. It is preferred also to reduce the particular chloride or chlorides at a higher temperature within the temperature range to reducev the reduction time.

In accordance with the practice. of the present invention, a coherent metallic member of nickel was produced from nickel chloride powder which was formed into a one-quarter inch tablet by pressing at 2000 pounds per square inch. The preshaped nickel chloride tablet was positioned within a chamber. Hydrogen gas was introduced into the chamber at a pressure of one atmosphere and the preshaped metallic chloride was heated to a temperature of 600 C., over a period of seventy minutes. The gas stream and heat were then discontinued and the apparatus was allowed to cool to room temperature. It will be noted from the single ligure of the drawing that a minimum temperature of about C. could have been selected to reduce the preshaped nickel chloride member to nickel. It is more desirable from an economic standpoint to employ a higher temperature for the reduction of the metallic chloride thereby reducing the reduction time. While hydrogen gas was employed as the reducing agent, other gas streams can be used provided the essential active reducing ingredient of such a stream is hydrogen.

Several examples of methods of forming coherent metallic members in accordance with the present invention are as follows:

Example l Nickel chloride powder was formed into a preshaped one-quarter inch tablet by pressing at 2000 pounds per square inch and was positioned within a chamber into' which was introduced hydrogen gas at a pressure of one atmosphere. The preshaped metallic chloride was heated to a temperature of 600 C. over a period of seventy mina utes. The heat was then discontinued and the apparatus was allowed to cool to room temperature. The coherent nickel member was l14 percent of theoretical density. Subsequently, the nickel tablet was sintered at a temperature of 1-350 C. for a period of ten minutes in a hydrogen atmosphere. The member was then 62 percent of theoretical density.

Example II Thirty grams of nickel chloride powder and 10.5 grams of chromium trichloride powder were mixed together and pressed into the shape of a bar at a pressure of 2000 pounds per square inch. 'This preshaped bar was then placed -into a chamber into which hydrogen gas was intro- `duced at a p-ressure of one atmosphere. The bar was heated to a temperature of 600 C. over a period of eighty minutes. yIt was then heated to 1100 C. for tive minutes and heated to 1350 C. Vfor ten minutes. The heat was then discontinued and the apparatus was allowed to cool to 'room temperature. A coherent nickel-chromium alloy bar of 20 weight percent-chromium and 8O weight percent nickel -was produced by this method. The bar showed approximately 50 percent linear shrinkage.

EXAMPLE III A mixture of nickel chloride powder and chromium trichloride powder and an inert non-metallic filler of magnesium silicate were mixed together to give 40 volume percent filler and preshaped into the form of a bar by pressing at 2000 pounds per square inch. The preshaped member was positioned in a chamber into which hydrogen gas was introduced at a pressure of one atmosphere. The preshaped member was heated to a temperature of 600 C. over a period of 80 minutes. It was then heated to 1100 C. for ve minutes and |heated to 1350 C. for ten minutes. The heat was then discontinued and the apparatus was allowed to cool to room temperature. A coherent nickel-chromium alloy bar of 20 weight percent chromium and 80 weight percent nickel was produced by this method in which magnesium silicate particles were dispersed throughout the volume of the b'ar.

While other modifications` of this invention and variations of method which may be employed within the scope of the invention have not been described, the invention is intended to include such that they may be embraced within the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A method -of forming a coherent metallic member which comprises forming at least one metallic halide powder into a preshaped powder member, positioning said preshaped member within a chamber, introducing into said chamber a stream of gas consisting essentially o'f hydrogen, and heating said member to a temperature in a temperature range having a lower limit in a range determined by the hydrogen halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of said member and with said member in a range from 0.001 to 0.01, and an upper limit in la range determined by the metallic halide vapor pressure multiplied by the number of halide atorrns per metallic atom in a range from 0.001 to 0.01 whereby said member is reduced to a coherent metallic member.

2. A method of forming a coherent metallic member which comprises forming a mixture of metallic halide powders into a preshaped powder'member, positioning said preshaped member within a chamber, introducing into said chamber a stream of gas consisting essentially of hydrogen, and heating said member to a temperature in `a temperature range having a lower limit in a range determined by the hydrogen -halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of said member and with said member in the range from 0.001 to 0.01, and an upper limit in a range determined by the metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in :a range from 0.001 to 0.01 whereby said member is reduced to a coherent metallic member.

3. A method of forming -a coherent metallic member which comprises forming at least one mixed metallic halide powder into a preshaped powder member, positioning said preshaped member within a chamber, introducing into said chambera stream of gas consisting essentially of hydrogen, and heating said member toa temperature in a temperature range having a lower limit in a range determined by the hydrogen halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of said member and with said member in a range from 0.001 to 0.01, and an upper limit in a range determined by the metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in a range from 0.001 to 0.01 whereby said member is reduced to `a coherent metallic member.

4. A method of forming a coherent metallic member which comprises forming at least lone metallic halide powder and iat least one powder containing a metal adapted to form an intermetallic :compound with the metal reduced from the metallic halide into a preshaped powder member, positioning said preshaped member within a chamber, introducing into said chamber a stream of Lgas consisting essentially of hydrogen, and Iheating said member to a temperature in a temperature range having a lower limit in a range determined by the hydrogen halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of said member and with said member in a range from 0.001 to 0.01, and an upper limit in a range determined by lthe metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in a range from 0.001 to 0.01 whereby said member is reduced to a coherent metallic member.

5. A method of forming a coherent metal which comprises forming at least one metallic halide powder and at least one inert metallic ller into a preshaped powder member, positioning said preshaped member within a chamber, introducing into said chamber a stream of gas, consisting essentially of hydrogen, and heating said member to a temperature in a temperature range having a lower limit in a range determined by the hydrogen halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of said member and with said member in a range from 0.001 to 0.01 and an upper limit in a range determined by the metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in a range from 0.001 to 0.01 whe-reby said member is reduced to a coherent metallic member.

6. A method of forming a coherent metallic member which comprises forming at least one metallic halide powder and at least one inert non-metallic ller into a preshaped powder member, positioning said preshaped member within a chamber, introducing into said chamber a stream of gas consisting essentially of hydrogen, and heating said member ,to a temperature in a temperature range having a lower limit in a range determined by the hydrogen halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal -of said member and with said member in a range from 0.001 to 0.01, and an upper limit in a range determined by the metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in a range from 0.001 to 0.01 whereby :said member is reduced to a coherent metallic member.

7. A method of forming a coherent metallic member which comprises forming at least one metallic halide powder, at least one reacting meta-l, and at least one inert metallic filler into a preshaped powder member, positioning said member within la chamber, introducing into said chamber a stream of gas consisting essentially of hydrogen, and heating said member to a temperature in a temperature range having a lower limit in a range determined by the hydrogen halide partial pressure to the 'hydrogen partial pressure ratio in equilibrium' with the metal of said member and with said member iu a range from 0.001 to 0.01, and an upper limit in a range determined by the metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in a range from 0.001 to 0.01 whereby said member is reduced to a coherent metallic member.

8. A method of forming `a coherent metallic member which comprises forming at least one metallic halide powder, at least one reacting metal, and at least one inert non-metallic filler into a preshaped powder member, positioning said member within Ia'chamber, introducing into said chamber a stream of gas consisting essentially of hydrogen, and heating said member to a temperature in a temperature range having a lower limit in a range determined by the hydrogen halide partial pressure to the hydrogen partial pressure ratio in equilibrium with the metal of said member and with said member in a range from 0.001 to 0.01, and an upper limit in a range determined by the metallic halide vapor pressure multiplied by the number of halide atoms per metallic atom in a range from 0.001 to 0.01 whereby said member is -reduced to a coherent metallic member.

References Cited by the Applicant UNITED STATES PATENTS 2,418,148 4/ 1947 Williams et al. 2,663,663 12/ 1963 Crowley. 2,664,352 12v/ 195 3 Darner.

FOREIGN PATENTS 551,859 6/ 1957 Canada. 644,813 10/ 1950 Great Britain. l 668,544 3/ 1952 Great Britain.

LEON D. RosDoL, Primary Examiner.

R. L. GRUDZIECKI, Assistant Examiner. 

1. A METHOD OF FORMING A COHERENT METALLIC MEMBER WHICH COMPRISES FORMING AT LEAST ONE METALLIC HALIDE POWDER INTO A PRESHAPED POWDER MEMBER, POSITIONING SAID PRESHAPED MEMBER WITHIN A CHAMBER, INTRODUCING INTO SAID CHAMBER A STREAM OF GAS CONSISTING ESSENTIALLY OF HYDROGEN, AND HEATING SAID MEMBER TO A TEMPERATURE IN A TEMPERATURE RANGE HAVING A LOWER LIMIT IN A RANGE DETERMINED BY THE HYDROGEN HALIDE PARTIAL PRESSURE TO THE HYDROGEN PARTIAL PRESSURE RATIO IN EQUILIBRIUM WITH THE METAL OF SAID MEMBER AND WITH SAID MEMBER IN A RANGE FROM 0.001 TO 0.01, AND AN UPPER LIMIT IN A RANGE DETERMINED BY THE METALLIC HALIDE VAPOR PRESSURE MULTIPLIED BY THE NUMBER OF HALIDE ATOMS PER METALLIC ATOM IN A RANGE FROM 0.001 TO 0.01 WHEREBY SAID MEMBER IS REDUCED TO A COHERENT METALLIC CHAMBER. 